The present invention relates to voltage level shifting, and, more particularly, to using DC motors to shift the level of DC reference voltages.
For integration into electronic systems, electronic devices accept available ground references for DC power supply voltages. In some instances, the electronic device may require a DC voltage which is different than the electronic system into which it is being integrated, resulting in incompatible ground references. For example, the electronic device may require a 5V TTL logic level while the electronic system may output xe2x88x9248V (having a 48V reference to ground). Typically, DC-to-DC converters are used to shift the voltages of the system so that the voltages and the ground references correspond with the specifications for the electronic device. DC-to-DC converters, however, require valuable space and are very expensive.
In accordance with one aspect of the present invention, an apparatus is provided for producing a floating DC voltage source from an electric motor. The apparatus includes a rectifier for rectifying a back electromotive force voltage from a winding of the motor and a clamping circuit which clamps the rectified voltage to produce a floating DC voltage. Switching off the winding from a motor control circuit connected to the motor produces the back electromotive force voltage. The DC motor may be a DC brushless motor, the winding may be a stator winding, and the DC voltage may be a TTL logic level voltage.
In accordance with another aspect of the present invention, a method is provided for producing a floating DC voltage source from an electric motor. The method includes rectifying a back electromotive force voltage from a winding of the electric motor to produce a rectified voltage and clamping the rectified voltage to generate a floating DC voltage. Switching off the winding from a motor control circuit connected to the motor produces the back electromotive force voltage. The DC motor may be a DC brushless motor, the winding may be a stator winding, and the DC voltage may be a TTL logic level voltage.